There has been proposed a conventional technique of measuring a consumed power value and comparing the consumed power value with a reference power value, in order to check presence or absence of electric power consumption while a user is out, etc., and inform the user of the result, thereby preventing electric power from being consumed during the user's absence (see e.g., Document 1: JP 2007-132804 A). The technique in Document 1 is to determine that the user has forgotten to turn off an electric load when the consumed power value measured is equal to or more than the reference power value.
But, an electric load, such as a clothes iron or an air-cleaning machine, automatically repeats on/off while it is operating. Accordingly, even during actually operating, when the power value is measured in an off period and compared with the reference power value, the electric load may be incorrectly determined to be in non-operation. That is, as the technique in Document 1, in case of the configuration of comparing the consumed power value measured while the user is out, etc., with the reference power value, there is a possibility that it is impossible to correctly detect that the electric load is operating.